A variety of equipment may be used in the manufacture of disk drive media to form the different magnetic and non-magnetic layers. In a typical process, a glass or aluminum substrate travels sequentially through a number of stations at which different materials are deposited under different conditions. For example, one or more sputtering systems may be used to sputter magnetic and/or non-magnetic materials onto the media.
In conventional sputtering processes, active sputtering stations for the media must be separated by finite distances. Without such separation, electromagnetic interference might occur between the stations and result in inhomogeneous sputtering or even equipment failure. Thus, the sputtering stations are physically separated, or, if closely situated, the sputtering stations may not be not used concurrently. Indeed, in some sputtering systems, sputtering components may be shared between adjacent sputtering stations and may be moved back and forth between them as the active sputtering station changes.
Anelva Corporation of Fuchu, Japan produces equipment that may be used to manufacture magnetic recording media such as hard-disks. Anelva supplies a unit designated as the C-3040. The unit includes a main chamber, entrance and output load locks, substrate load and unload stages and a plurality of processing stations. Disks are fed into the system, transported and treated in processing stations, and then are fed from the system as disks ready for use as hard disks in computer applications. Patents describing this system are U.S. Pat. Nos. 6,740,209, 6,027,618, 6,228,439 B1 and 6,251,232 B1.
U.S. Pat. No. 6,740,209 describes an apparatus to be used in manufacturing magnetic recording media. FIG. 1 is a schematic side cross sectional view of the apparatus. FIG. 1 comprises a deposition chamber 1, a substrate holder 90 to locate at least one substrate 9 at a required position in the deposition chamber 1, and multiple cathode units 3 for sputtering discharge.
The deposition chamber 1 is an air-tight vacuum chamber comprising an opening (not shown) for transfer-in-and-out of the substrate 9. The opening is shut and opened by a gate valve (not shown). The deposition chamber 1 comprises a gas introduction line 12 to introduce an argon gas for the sputtering discharge into the inside.
The substrate holder 90 holds the substrate 9 in a vertical position. The substrate holder 90 is capable of holding multiple substrates 9 on the same vertical plane, and at the same height.
FIG. 2 (front view) and FIG. 3 (side view) show schematic views of the substrate holder 90 in the apparatus shown in FIG. 1. As shown in FIG. 2, the substrate holder 90 comprises multiple small “holder magnets” 96 at the bottom. Each holder magnet 96 has a magnetic pole on the top and the bottom. The magnetic poles of the holder magnets 96 are alternatively opposite in the array direction.
Beneath the substrate holder 90, a magnetic-coupling roller 81 is provided, interposing a partition wall 83. The magnetic-coupling roller 81 is a cylinder, on which two spirally elongated magnets 82 are provided as shown in FIG. 2. These magnets 82 are hereinafter called “roller magnets”. The surface pole of each roller magnet 82 is opposite to each other. The magnetic-coupling roller 81 has a so-called double-helix structure. The magnetic-coupling roller 81 is provided at a position where the roller magnets 82 face to the holder magnet 96 through the partition wall 83. The partition wall 83 is formed of material that would not disturb the magnetic field, e.g. non-magnetic material. The holder magnets 96 and the roller magnets 82 are magnetically coupled with each other. The magnetic-coupling roller 81 is provided along the transfer line of the substrates 9.
Multiple main pulleys 84 that are rotated around horizontal axes are provided along the transfer line. As shown in FIG. 3, the substrate holder 90 rides on the main pulleys 84. A couple of sub-pulleys 85, 85 are in contact with the lower margin of the substrate holder 90. The sub-pulleys 85, 85 pinch the lower margin of the substrate holder 90 to prevent the substrate holder 90 from falling. The multiple sub-pulleys 85, 85 are provided along the transfer line as well.
As shown in FIG. 3, a drive rod 86 is connected with the magnetic-coupling roller 81 through a bevel gear. A motor 87 is connected with the drive rod 86 so that the magnetic-coupling roller 81 can be rotated around its center axis by driving force transferred from the motor 87 through the drive rode 86. When the magnetic-coupling roller 81 is rotated, the double-helix roller magnets 82 shown in FIG. 2 are also rotated. When the roller magnets 82 are rotated the plural aligned small magnets of which poles are alternately opposite move simultaneously along the aligning direction. Therefore, the holder magnets 96 magnetically coupled with the roller magnets 82 also move linearly as the roller magnets 82 are rotated, resulting in the substrate holder 90 moving linearly as well. During this liner movement, the main pulleys 84 and the sub-pulleys 85, 85 shown in FIG. 3 are driven to rotate, following the movement.
Unfortunately, physical or temporal separation of processing stations results in having to transport disks using such above described mechanical transport systems including disk carrying devices. Such mechanical transport systems are susceptible to mechanical wear which in turn produces contamination byproducts. The friction coefficient in a drive mechanism can be large and a lubricant cannot be used due to the vacuum requirements. For example, the main pulleys 84 and the sub-pulleys 85 shown in FIG. 3 are susceptible to mechanical wear and produce contamination byproducts.
The contamination byproducts may take on the form of magnetic metal debris or ferrous metal debris (magnetic particles). These magnetic particles cause contamination of target materials and cause voids in the deposited films which can lower the yield and throughput in the manufacturing of magnetic media. An object of the present invention is to provide a magnetic particle trapper device to capture the magnetic particles to reduce the target contamination and reduce the voids in the depositing films from such magnetic particles. There is therefore a need for an improved mechanical transport system having at least one magnetic particle trapper device.